The Cetti’s warbler is a small stocky bird with a chestnut brown back and head, a grey belly and breast, and a pale almost white throat. They have a relatively long tail which is often cocked upwards like that of a wren. They are most common in southern England and the best way to recognise them is by their loud outbursts of bubbly song. While the male is slightly bigger, they are monomorphic, meaning males and females look almost identical and are difficult to tell apart.
Average Length: 13 - 14 cm
Average Lifespan: 2 Years
Average Wingspan: 15 - 19cm
Cetti’s Warblers are insectivorous and feed mostly on insects and their larvae. They usually take these insects from the ground but can occasionally be seen taking them from the surface of the water or in flight. The availability of these insects can drive these warblers to move to reedbeds after the breeding season to feed up and recover.
How to feed cetti's warbler: They will sometimes eat seeds but would prefer mealworms, so put these outside for them to feast on.
What to feed cetti's warbler: If you live near a population, create an insect-friendly garden that these warblers can make use of.
Cetti’s warblers begin their breeding season in April when they build an untidy nest out of leaves and dry grass and line it with softer material such as feathers and hair. The female then lays 4-5 brick red eggs which she incubates alone for 17 days and then feeds for a further 14-15 days. During this time the male defends the nesting territory. Once the chicks fledge, they are fed and looked after by both parents for a final 2 weeks. The female will then often lay and raise a second clutch before the breeding season ends in August.
While the Cetti’s Warbler is doing very well in the UK common threats such as habitat loss may drive a population decrease. Cetti’s Warblers inhabit very specific and relatively fragile ecosystems such as reedbeds and river bank (riparian) habitats. The loss of these habitats through development or fires, such as the Wirral reedbed fires, could endanger these small warblers.
Visit and support reedbed and wetland habitat reserves in the south of England.
Petition local areas to protect riparian and reedbed habitats.
Support your local rivers trust to clean the rivers and the surrounding habitat to keep them in good shape for wildlife.
Cetti’s Warblers are the only UK bird to have only 10 tail feathers instead of the usual 12.
Araújo, P. M., Lopes, P. B., Da Silva, L. P., & Ramos, J. A. (2016). The Importance of Reedbeds and Riparian Areas for Cetti’s Warbler Cettia cetti throughout its Annual Cycle. Wetlands. https://doi.org/10.1007/s13157-016-0799-7
BirdLife International (2023) Species factsheet: Cettia cetti. Downloaded from http://datazone.birdlife.org/species/factsheet/cettis-warbler-cettia-cetti on 08/08/2023.
British Trust for Ornithology (no date) Cetti’s warbler | BTO - British trust for ornithology. Available at: https://www.bto.org/understanding-birds/birdfacts/cettis-warbler (Accessed: 08 August 2023).
Robinson, R. A., Freeman, S. N., Balmer, D. E., & Grantham, M. J. (2007). Cetti’s Warbler Cettia cetti: Analysis of an expanding population. Bird Study, 54(2), 230–235. https://doi.org/10.1080/00063650709461479
RSPB (no date) Cetti’s warbler facts: Cettia Cetti, The RSPB. Available at: https://www.rspb.org.uk/birds-and-wildlife/wildlife-guides/bird-a-z/cettis-warbler/ (Accessed: 08 August 2023).